Barack Obama last night re-established the Democrats as a national political party, performing strongly against John McCain in the US industrial heartland, the Rocky Mountains and the south.

The sweep of Obama's victories, as the night wore on, suggested he was poised to win by a bigger margin than Bill Clinton, who was elected in 1992 with just 43% of the vote. Obama also appeared to have fulfilled his promise of remaking the Democrats' electoral map by contesting outside the traditional battleground states, and striking deep into Republican territory in the south and in the west.

He was also holding his own among working class white males, the prime demographic territory of the Republican party. White males had been lukewarm to John Kerry in 2004 and to Al Gore in 2000. That resistance to Democrats appeared to have shifted with the economic crisis, giving Obama greater purchase in ailing industrial states like Ohio, Pennsylvania and Michigan.

Last night he took Ohio, which defeated Kerry's campaign and was at the top of his aspirations. He held three rallies there on Sunday night, and deployed his army of volunteers to knock on a milllion doors before polling day. Television networks also gave Iowa and New Mexico to Obama and he held on to Pennsylvania, putting paid to McCain's hopes of finding a path to the White House by that route, and he was leading in early results from Colorado.

In the South, Obama was ahead in Florida and Virginia - defying the Republican lock on the states of the old confederacy.

For McCain, the night was over even before polls had closed in California when the networks projected a comfortable victory for Obama in Pennsylvania. With its 21 electoral college votes, Pennsylvania was one of the biggest prizes of the election, along with Florida and Ohio, and the only one held by Democrats in 2004.

McCain had famously cast the contest for Pennsylvania as his last stand and as it turned out, it was. With Pennsylvania off the table, his only hope was to try to hold off a surge and hang on to every state won by George Bush in 2004. But as the night wore on, it became clear those hopes would not materialise.

New Hampshire, the most McCain-friendly state in his two attempts at winning the White House, also went for Obama. McCain had won New Hampshire in the 2000 Republican primary against George Bush - only to see his hopes extinguished in the south. In 2007, New Hampshire was also the scene of McCain's improbable comeback in the Republican primary.

With its fierce tradition of independent voting, McCain early on had been hopeful of winning New Hampshire against Obama.

McCain did manage to hold off a challenge from Obama in Georgia, an extreme longshot for the Democrats. But that was small compensation after the loss in Pennsylvania, and the slow collapse of McCain's presidential quest.

The McCain camp had ranked Pennsylvania their top prospect among states they hoped to capture from the Democrats - the equaliser in the event of wins by Barack Obama in Ohio, Florida and other battleground states held by Republicans.

In the final days of his failing campaign, the McCain camp had thrown all of its resources into Pennsylvania, ramping up advertising spending, and hunting for votes in small towns and rural areas.

The effort had puzzled political strategists. Opinion polls had consistently shown Obama with double-digit margins in the state.

But the McCain camp insisted it saw an opening, and that the gap was narrowing in its favour.

The thinking behind that laser like focus on Pennsylvania - which saw McCain this week visiting the town of Moon Township, population 22,000 - was that Obama had failed to seal the deal with conservative white voters in the hinterland

Obama had lost by wide margins to Hillary Clinton in the primary last April in a contest overshadowed by his ill-judged comments about working class voters clinging to guns and religion.

He was put on the defensive once more when video clips surfaced of his former pastor, the Rev Jeremiah Wright, declaring in a now infamous sermon: God damn America.

In north-eastern portions of the state, dominated by working class whites and Catholics, Clinton ran away with 70% of the vote.

In the six months since the primary, Obama devoted considerable resources to building a network in Pennsylvania. With the primary over, he also inherited an important new ally in the state's governor, Ed Rendell. But issues of race did not entirely evaporate. Despite Obama's efforts, John Murtagh, a Democratic member of Congress, expressed doubts last month that white voters in Pennsylvania were ready to vote a black man into the White House.

In the last 72 hours before election day, Republican groups in the state put out a new television ad using clips of Wright.

In the event though, Murtagh got it wrong. In exit polls across the country, 90% of voters said race was not a factor in their decision - and it was not in Pennsylvania.